Saturn Vue fan problem

As soon as i turn on my heater or Ac my cooling fan comes on and stays on until i shut off my fan in the cabin.

What year? What engine? If you have the HVAC control head set in defog or a/c it is normal for the cooling fan to run.

It's a 2004 Vuw 4 cyl. Normally if i start it the fan doesn't come on, as soon as i trun on heat the fan turns on,even when it is cold and i first start the truck. It never use to do that

Sorry, even if i have it set for floor heat it comes on.I had the rad flushed and changed coolant since it has 160,000 kms on it but no difference. I thought about the thermostat but i get good heat from it and the temp gauge is where it should be.

Would need to check for any codes stored, also would need to monitor inputs to the ecm as well as ecm ouputs. That way you would be able to see what coolant temp the ecm is reading, a/c pressure switch reading, hvac commanded status, ect..., car should be taken to a capable shop for diag.